4.4.7: Project Summary Pollen allergies afflict over 35 million Americans, and the economic cost of treating these allergies exceeds 12 billion dollars annually. The effects on human health are considerable because pollen exposure also increases the risk of developing asthma and can trigger fatal asthma attacks. Despite the importance of these public health concerns, urban areas are filled with plants that produce allergenic pollen, many of which are intentionally cultivated. This preventable situation is caused by a lack of knowledge concerning: 1) how pollen production and dispersal from individual plants leads to heterogeneity in airborne allergenic pollen concentrations on small spatial scales (e.g., tens to hundreds of meters); and 2) the extent to which exposure to allergenic pollen is responsible for triggering asthma attacks and other respiratory symptoms. This project's objective is to quantify these processes and show how allergenic pollen producing plants affect human health. The main components of this research include: ? Characterizing pollen production and spatial dispersal patterns using a pollen sampling field study focused on Norway maple (Acer platanoides), white mulberry (Morus alba), box elder (Acer negundo), and common ragweed (Ambrosia artemisiifolia); ? Creating a spatially explicit model of airborne pollen concentrations as a function of plant composition using a comprehensive street tree database; ? Adding a temporal dimension to the spatial pollen count predictions using meteorological data, daily pollen count data from a National Allergy Bureau pollen counting station, and a small citizen science plant phenology monitoring program; and ? Linking pollen exposure to health effects including asthma attacks and respiratory symptoms, using existing datasets collected in the study area, Detroit, MI. These include respiratory related hospital visits extracted from geocoded Medicaid claims data and cohort studies that tracked 255 children's respiratory health for >12 months. Understanding the contribution of particular plants to pollen concentrations in urban areas has will allow land owners, municipalities and others to actively manage plant composition to reduce allergenic pollen exposure and its health effects. These translational benefits are especially important in both highly vegetated and shrinking cities, such as Detroit, where large vacant areas are providing habitat for allergenic plants that likely exacerbate health disparities.